Really, wordpress is getting more and more complicated every day, obviously Gutenberg blocks are only suitable for professionals. It makes the web heavier and is quite slow, redundant and confusing.
How to disable block editor widget on WordPress 5.8
Here I share the code to turn it off in the widget area to make the widget go back to the old version of WordPress. Just insert this code into the functions.php file in your current theme directory dc.

Method 1: Use code in Function.php of theme
// Disables the block editor from managing widgets in the Gutenberg plugin.
add_filter( ‘gutenberg_use_widgets_block_editor’, ‘__return_false’ );
// Disables the block editor from managing widgets.
add_filter( ‘use_widgets_block_editor’, ‘__return_false’ );
Method 2: Use a plugin
And you just need to install this plugin to get https://wordpress.org/plugins/classic-widgets/
Good luck